Portable air-pump.



No. 670,8". Patented Mar. 26, mm, J. C. PHELPS.

PORTABLE AIR PUMP.

(Application filed Sept. 30, 1899.)

(No Model.)

" Jay:-

UNITED STATES PATENT ()EEIcE.

JAMES C. PHELPS, OF SPRINGFIELD, MASSACHUSETTS.

PORTABLE AIR-PUMP.

SPECIFICATION forming part of Letters Patent No. 670,81 1, dated March26, 1901.

Application filed September 30, 1899. Serial No. 732,156. 1110 model.)

To (ZZZ whom, it may concern:

Be it known that 1, JAMES C. PHELPS, a citizen of the UnitedStates,residing at Springfield, in the county of Hampden and State ofMassachusetts, have invented new and useful Improvements in PortableAir-Pum ps, of which the following is a specification.

This invention relates to portable airpumps, the object being to providean improved valveless multiple-piston pump of this class which isadapted for forcing air into different objects with the expenditure of amoderate degree of power and which provides improved means for operatingthe pump and for guarding the several pistons against injury fromhandling and against the admission of injurious matters into theirexposed extremities; and theinvention consists in the peculiarconstruction and adaptation of the various parts of the instrument,whereby the aforesaid objects are attained.

In the drawings forming part of this specification, Figure l is alongitudinal sectional view of an air-pn mp embodying my improvedconstruction, said view illustrating the closed positions of the severalparts and showing in like section an auxiliary air-conductor within thecentral piston or part. Fig. 2 is a side elevation of the pump, showingthe parts thereof in operative positions and said auxiliary conductorconnected thereto.

Referring to the drawings, 2 indicates the outer tubular case of thepump or the barrel thereof, as ordinarily termed. A thimblebushing 7 isscrew-connected within the upper end of said case, and an air-outlet 6is provided at the lower end. A hollow piston 4 operates directly withinsaid case or barrel and extends through said bushing and is of slightlyless diameter than the interior thereof, to the end that more or lessair may be drawn into said case between the latter and the bushing bythe movement of said piston inwardly. Said bushing also provides a stop,which lim its the outward movement of said piston when the plate overthe packing thereof at 10 is brought thereagainst. Said piston 4 has athimble-bushin g 9 screw-connected to its outer end, through the top ofwhich is an air-inlet opening m, which may be utilized in case of needfor admitting more air into the case between the pistons than will beprovided by the spaces between the pistons and inner walls of thebushings. A second piston 3 operates within said piston 4 and the saidbushing 9 and provides the actuating medium for the last-named piston,the piston 3 and its said inclosing bushing 9 being mutually fitted oneto the other in the manner and for the purpose described relative to thepiston 4 and the bushing 7. The said piston 4 has a means of aircommunication between the interior thereof and the space in the lowerend of said case 2, consisting of the hollow screw, (shown at 12,) onwhich is a nut,

said screw holding the said packing and its back plate 10 against theend of the piston. The said two pistons 4 and 3 are similarly packed attheir inner extremities by means of a hat-brim leather packing, asindicated,

having a suitable oil or other softening-lubrt cant applied thereto.Said soft packings are secured against the ends of the pistons oragainst a plate thereon, as shown at 8 and at 10, Fig. 1, but having thedepending circumferential borders of said packings extendingsufficiently beyond the borders of their supporting-plates or pistonends to permit the air which is compressed in the spaces above saidpackings when the pistons are quickly So drawn out, as in Fig. 1, topass by said packings and enter the spaces below each piston in saidcase 2 and in said piston 4, and thereby supplying air under each ofsaid pistons,

which is eventually, as below set forth, forced out through said outlet6. The said packing on the inner end of said piston 3 is secured theretoby a plug 13, preferably of wood, which is screwed thereto, as shown.The outer end of this last-named piston has thereon, either integraltherewith or otherwise, a combined piston-cover 5 and handle foroperating the device. Said cover, as shown, effectually incloses andprotects the outer extremities of said case 2 and the piston 4 againstthe en- 5 trance of dirt and also protects said inclosed extremitiesfrom injury while being transported or handled while in the closedcondition. (Shown in Fig. 1.) It is found also in The herein-describedair-pump may be employed for inflating a variety of obj ects,am ongwhich are bicycle-tires, and when so used it is convenient to have anauxiliary (flexible or otherwise) air-conducting pipe at hand forconnecting the case 2 with the object to be inflated. Therefore the saidcentral piston 3 is made hollow from the inner end of said plug 13through the center of the end of said cover and handle 5, and in saidpiston is shown in Fig. 1 said auxiliary connecting-tube, (thereindicated by 14,) the extremities of which are provided with screwedcouplings for connection between the air-pump and an object to beinflated, as stated, one end of said tube 1-4: being screwed into saidair-outlet 6 in the lower end of the case 2. For the purpose ofretaining said tube 14 within said inner piston 3 any suitable means maybe provided similar to a strip of spring metal 15, shown secured to theinner end of said plug 13, having upwardly-extending spring-armsengaging the lower end of said auxiliary tube 14, whereby the latter isprevented from dropping out when the device is handled in the ordinaryWay.

In operating the within-described pump for inflating an object connectedto the pump at 6 the elongating movement of the parts for charging thecase 2 and the piston 4 with air brings them substantially to therelative positions shown in Fig. 2, such movements causing air to bedrawn into the case 2 through the said openings between the upper endsofsaid case and of the pistons 3 and 4, as described, and to pass saidpacking and to be directed into and below the piston 4 downwardlythrough said hollow screw into the case 2, thereby charging said-caseand piston 4 with air while the central piston 3 is being drawnoutwardly. Fig. 2 does not illustrate said piston 3 drawn entirely out.A quick downward thrust of said piston 3 drives the piston 4 down with aquick cushioned movement, owing to the inability of the air therein toescape quickly through the restricted passage in said screw 12, and thusconsiderably compressing the air in the case 2, the continued downmovement of said piston 3 now serving to increase the pressure in saidcase and in the object to which the latter may be connected. Rapidrepetitions of the movements of said two pistons quickly increase theair-pressure in said object as desired. The said restricted air-passagein the screw 12 prevents any inconvenient escape of air during saidpiston movements, and thus the pump,of simple construction, with novalves to become deranged, fully serves the described purpose.

Having thus described myinvention, what I claim, and desire to secure byLetters Patent of the United States, is-

An air-pump comprising a tubular case, having an air-outlet at one endand a thimblebushing 7 screwed into the opposite end, a hollow piston 4operating directly within this case and extending through the bushing,its diameter being slightly less than the latter so that air may bedrawn into the case between the piston and bushing, a thimblebushingscrewed to one end of the piston said bushing having an air-inletopening, a hollow screw in the opposite end of this piston, a packingand backing-plate held on the end of the piston by said hollow screw, aninner hollow piston, a backing-plate and packing on one of its ends, ascrew-plug for holding the packing on the piston, the inner ends of thethimble-bushings adapted to strike the backing-plates to act as stops tolimit the outward movement of the parts, said screw-plug havingspring-clamps thereon, and an auxiliary connecting-tube adapted to enterthe inner hollow piston and be held by the springclamps.

JAMES O. PHELPS. Witnesses:

H. A. CHAPIN, K. I. OLEMoNs.

